%% Facts
likes(wallace, cheese).
likes(grommit, cheese).
likes(wendolene, sheep).

%% Rules
%% "Rules are logical inferences about our world."
friend(X, Y)
%% :- is if and only if
:-
    %% \+ is negation -> if X is not Y
    \+(X = Y)
    %% , is and
    ,
    likes(X, Z)
    ,
    likes(Y, Z)
    %% . ends the rule
.

%% If two like the same thing, then those two are friends?
%% Meh.
